The Harkin-Shaheen proposal would gradually reduce the number of votes required to overcome a filibuster as time goes by. It might be seen as analogous to retail markdowns, in which merchandise on racks becomes cheaper the longer it remains unsold.

Under the Harkin proposal, the first vote for cloture (the term for ending a filibuster) would require 60 votes, as is current practice. But after a few days had passed, cloture would only require 57 votes. After a few more days, it would require 54, and so on. Eventually a bare majority of 51 votes would be enough.

Senator Harkin on Thursday pointed out that the use of the filibuster was once rare, averaging only one per Congress. But in the last Congress, the 110th, there were 139 motions for cloture. In the current Congress, the 111th, there have already been 74.

“Again and again, the minority party is abusing the rules of the Senate,” said Harkin. (The Senator from Iowa said nothing about the derivation of the word “filibuster”, which is really quite interesting.)

Harkin first introduced a similar measure in 1995. If nothing else, this shows how difficult passing such a measure might be.

For one thing, filibuster reform is subject to a filibuster. And changing Senate rules requires 67 votes, not just 60.

Thus you can count Senate majority leader Harry Reid (D) of Nevada among those who dismiss its chances.

“I’m totally familiar with his idea,” Senator Reid said Thursday of Harkin’s proposal. “It takes 67 votes, and that kind of answers the question.”

Furthermore, many Democrats know that their party will return to minority status at some point, and might then want the power of the filibuster to remain intact.

It calls for the Democrat presiding over the Senate at the start of the next Congress in January to declare that the Senate is not a “continuing body” and does not have to abide by rules passed decades ago.

Such an action would be unprecedented and would likely draw a ferocious Republican response.